Rhodium

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Rhodium Quick Reference

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Notes

Symbol

Rh

Atomic Number

45

Atomic Weight

Rounded

102.9

for regular calculations

Standard

102.90550 ± 0.00002

for precise calculations

Oxidation States

 6

less common

 5

less common

 4

less common with disagreement

 3

more common

 2

less common with disagreement

 1

less common

 0

less common

-1

less common

Pauling Electronegativity

2.28

Electron Configuration

Orbital Occupancy

[Kr] 4d8 5s1

[Kr] represents the closed-shell electron configuration of krypton

Orbital Filling Order

[Kr] 5s1 4d8

[Kr] represents the closed-shell electron configuration of krypton

Term Symbol

4F9/2

see expanded configuration ...

Ionization Energies

I   (1)

 7.45890 eV

II  (2)

18.08 eV   

III (3)

31.06 eV   

Electron Affinity

1.14289 ± 0.00020 eV

 9218.0 ± 1.5 cm-1  

Density

liquid, 2237.15 K

10.650 g/ml 

solid, 25 °C

12.400 g/cm3

Molar Volume

solid, 298 K, 1 atm

8.28 cm3/mol

Melting Point

1 atm

2236 K

ITS-90 first-quality, secondary reference point (freezing point)

Boiling Point

1 atm

4114 ± 90 K

reference stated that the uncertainty may be larger than indicated

Thermal Conductivity

solid

400 K

146 W/(m K)

300 K

150 W/(m K)

298.2 K

150 W/(m K)

273.2 K

151 W/(m K)

200 K

154 W/(m K)

see all 46 conductivities ...

Pyykkö Covalent Radius

single bond

125 pm

double bond

110 pm

triple bond

106 pm

Atomic Radius

134 pm

Enthalpy of Fusion

1 atm

21.55 kJ/mol

Enthalpy of Vaporization

1 atm

495.4 kJ/mol

Quantity

Rhodium Atomic Structure

Notes

Ionization Energies

I   (1)

 7.45890 eV

II  (2)

18.08 eV   

III (3)

31.06 eV   

Electron Affinity

1.14289 ± 0.00020 eV

 9218.0 ± 1.5 cm-1  

Electron Binding Energies

K    (1s)

23220 eV  

LI   (2s)

 3412 eV  

LII  (2p1/2)

 3146 eV  

LIII (2p3/2)

 3004 eV  

see all 12 energies ...

Electron Configuration

Orbital Occupancy

[Kr] 4d8 5s1

[Kr] represents the closed-shell electron configuration of krypton

Orbital Filling Order

[Kr] 5s1 4d8

[Kr] represents the closed-shell electron configuration of krypton

Term Symbol

4F9/2

see expanded configuration ...

Clementi-Raimondi Effective Nuclear Charge

1s

Orbital Exponent

44.0756

ζ

Principle Quantum Number

1

n

Effective Nuclear Charge

44.0756

Zeff = ζ × n

2s

Orbital Exponent

16.5773

ζ

Principle Quantum Number

2

n

Effective Nuclear Charge

33.1546

Zeff = ζ × n

see all 10 effective nuclear charges ...

Screening Percentage

86.2%

Fluorescence Yields

ωK

0.807

ωL1

0.013

ωL2

0.043

ωL3

0.046

Coster-Kronig Yields

F12

0.10

F13

0.57

F23

0.13

Quantity

Rhodium Physical Properties

Notes

Density

liquid, 2237.15 K

10.650 g/ml 

solid, 25 °C

12.400 g/cm3

Molar Mass

Rounded

102.9 g/mol

for regular calculations

Standard

102.90550 ± 0.00002 g/mol

for precise calculations

Molar Volume

solid, 298 K, 1 atm

8.28 cm3/mol

Physical Form

silvery-white metal

Linear Thermal Expansion Coefficient

25 °C

8.2×10-6 K-1

283 K

8.45×10-6 K-1

85 K

4.18×10-6 K-1

75 K

3.50×10-6 K-1

65 K

2.77×10-6 K-1

57.5 K

2.23×10-6 K-1

see all 20 coefficients ...

Specific Gravity

68 °F, water at 4 °C (39.2 °F)

12.41

Young's Modulus

379 GPa

Poisson's Ratio

0.260

Electrical Resistivity

solid, 295 K

4.8×10-8 Ohm m

Contact Potential

4.52 eV

Photoelectric Work Function

4.57 eV

Thermionic Work Function

4.80 eV

Superconducting Transition Temperature

0.000325 K

Superconducting Critical Magnetic Field at Absolute Zero

0.049×10-4 T

Mineralogical Hardness

6.0

Vickers Hardness

annealed at 1873 K for 1.5 hr, purity - 99.6%

293 K

1246 MN/m2

723 K

 942 MN/m2

1348 K

 461 MN/m2

Reflectivity

surface polished

0.5 μm

76%

0.6 μm

77%

0.8 μm

81%

see all 8 reflectivities ...

Isothermal Bulk Modulus

300 K

270.4 GPa

Isothermal Compressibility

300 K

0.00369 GPa-1

Gram Atomic Volume

8 cm3

Quantity

Rhodium Atomic Interaction

Notes

Oxidation States

 6

less common

 5

less common

 4

less common with disagreement

 3

more common

 2

less common with disagreement

 1

less common

 0

less common

-1

less common

Pauling Electronegativity

2.28

Allred-Rochow Electronegativity

1.45

Configuration Energy

electron volt units

9.259 eV

Pauling units

1.56    

Allred Electronegativity

oxidation state: 2

2.28

Ghosh-Gupta Electronegativity

3.4611 eV

Nagle Electronegativity

1.39

Pearson Absolute Electronegativity

4.30 eV

Chemical Hardness

3.16 eV

Cohesive Energy

per mole

554 kJ/mol    

per atom

  5.75 eV/atom

Quantity

Rhodium Thermodynamics

Notes

Melting Point

1 atm

2236 K

ITS-90 first-quality, secondary reference point (freezing point)

Boiling Point

1 atm

4114 ± 90 K

reference stated that the uncertainty may be larger than indicated

Thermal Conductivity

solid

400 K

146 W/(m K)

300 K

150 W/(m K)

298.2 K

150 W/(m K)

273.2 K

151 W/(m K)

200 K

154 W/(m K)

see all 46 conductivities ...

Critical Point

7000 K

Vapor Pressure

4114 K

1 atm

4110 K

1 bar

3530 K

1×10-1 bar

3102 K

1×10-2 bar

2236 K

5.050×10-6 bar

melting point

see all 19 pressures ...

Enthalpy of Fusion

1 atm

21.55 kJ/mol

Enthalpy of Vaporization

1 atm

495.4 kJ/mol

Isobaric Molar Heat Capacity

298.15 K, 1 bar

24.98 J/(mol K)

Isobaric Specific Heat Capacity

298.15 K, 1 bar

0.243 J/(g K)

Electronic Heat Capacity Coefficient

4.65 mJ/(mol K2)

Debye Temperature

Low Temperature Limit ( 0 K )

512 K

Room Temperature ( 298 K )

350 K

Quantity

Rhodium Identification

Notes

CAS Number

7440-16-6

ICSC Number

powder

1247

RTECS Number

VI9069000

Quantity

Rhodium Atomic Size

Notes

Atomic Radius

134 pm

Orbital Radius

136.4 pm

Pyykkö Covalent Radius

single bond

125 pm

double bond

110 pm

triple bond

106 pm

Cordero Covalent Radius

142 pm

Shannon-Prewitt Crystal Radius

ion charge: +3, coordination number: 6

80.5 pm

ion charge: +4, coordination number: 6

74 pm  

ion charge: +5, coordination number: 6

69 pm  

Shannon-Prewitt Effective Ionic Radius

ion charge: +3, coordination number: 6

66.5 pm

ion charge: +4, coordination number: 6

60 pm  

ion charge: +5, coordination number: 6

55 pm  

Batsanov Crystallographic Van Der Waals Radius

2.0×102 pm

Batsanov Equilibrium Van Der Waals Radius

232 pm

Slater Atomic-Ionic Radius

135 pm

Quantity

Rhodium Crystal Structure

Notes

Nearest Neighbor Distance

300 K, 1 atm

269 pm

Atomic Concentration

300 K, 1 atm

7.26×1022 cm-3

Quantity

Rhodium History

Notes

Discovery

date of discovery

1803

discoverer

William Hyde Wollaston

birth

August 6, 1766

death

December 22, 1828

location of discovery

London, England

Origin of Element Name

origin

rhodon

origin description

color—Greek for rose or rose colored

Origin of Element Symbol

symbol: Rh

origin

rhodium

origin description

element name

Formerly Used or Proposed Element Names and Symbols

symbol

R

Quantity

Rhodium Abundances

Notes

Earth's Crust

1×10-3 ppm

Earth's Mantle

0.93 ppb

primitive mantle

Earth's Core

0.74 ppm

Bulk Earth

0.24 ppm

U.S. Coal

<0.001 ppm

estimated from USGS and literature data

Solar System

0.344

number of atoms for every 106 atoms of silicon

Sun

1.12 ± 0.12

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Meteorites

1.08 ± 0.08

base 10 log of the number of atoms for every 1012 atoms of hydrogen

Quantity

Rhodium Nomenclature

Notes

Element Names in Other Languages

French

rhodium

German

Rhodium

Italian

rodio

Spanish

rodio

Portuguese

ródio

Anions or Anionic Substituent Groups

rhodide

Cations or Cationic Substituent Groups

rhodium

Ligands

rhodido

Heteroatomic Anion

rhodate

'a' Term—Substitutive Nomenclature

rhoda

'y' Term—Chains and Rings Nomenclature

rhody

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